Burlington weekly free press. [volume] (Burlington, Vt.) 1866-1928, 1887-03-04
ORIGIN AND PROPERTIES OF SOILS.



Friday afternoon, was delivered by
Prof w. w Cooke, on the subject, "Ori-
gin and Properties of Soils" The pro.
lessor said; Take any of the woods
around here. and you will lind in them
native plants that have become accus-
toned to that soil If the seeds of these
plants should be carried over into differ
ent kind of soil, the plants would be
obliged to struggle for existence. Some
would be able to adapt themselves to the
new conditions, while others, whose char.
acter had become more fixed, would not
he able TO change il and would cease to
survive The soil in nature cannot
change. But in the case Of agriculture
the opposite is true. In nature the plant
must change to suit the soil in agricul-
ture we change the soil to suit the plant
IN order to do this we must know some
thing about the soil, where it comes from
ana what its properties are. All
soil was originally rock, that has
become deCompOSed. Now there are
various ways in which Il rock is deCom
posed to make soil. 1t may be cut by the
action of the wind and rain The rocks
may Crumble with frost. This is n purely
mechanical action. Then the air has AN
other action on the rock which is Chemi-
cal. The rock may rot, Just as truly as
wood riots. Rotting is oxidation or burn
ing. Rocks may also he dissolved, either
partly or wholly, by the old solvent,
water. Water, with "A little alkali and
under heat and pressure will dissolve any
rock. The rain water has quite an action
on lime rocks and others, but this effect is
increased by carbonc acid gas. We may
also have these rocks ground to pieces by
the ice and later on the soil may change
in its character by the action of floods,
running water These two last causes
have produced principally, the biologists
tells Us, the soil of Vermont. AT first this
soil was a kind of gravel; but at the end
of the glacial period there were great
hoods, and through the action of this
water the materials left by the
glaciers were worked over ana
sitted, leaving them more in such
Il condition As we have them now. The
current deposits the COarscr materials
first and the finer later. Silt and clay are
carried by scarcely any motion of the
water. and in fact clay is held in suspen-
SION by water for a long Time after the
latter has become entirely still. 1t is on
this principle of the sorting power of
water that the present methods of soil
analysis are founded According to the
size of the rock materials in the
sol, and the vegetable elements pres
eut we may divide soils into stony
soil, graveiiv. sandy, loan soil. clay,
muck and peat. When the floods worked
overthe materials left by the glaciers they
carried the fine material into the outeys.
leaving the StOnler materials on the hill
slopes At the foot of the slopes you find
either graVelly soil or beds Of the original
glacial drift. Further down we find the
pure sand. There are two kinds Of sandy
soil. one of them comes from the dSn.
teGratlon of sand rock. There is very
little OF this kind of soil in Vermont
The sand soils OF Vermont are formed by
the sitting action of the water. When
we get the sand ground up still finer we
nave the silt sOl and this is always
formed by the sitting action of water The
loan Is a mixture of the clay with either
the gravelly or sandy soil There is also
good deal of vegetable matter present
The clay, like the sand, may be from two
different sources. Clay always comes
from the dlsintegratlOn Of rocks. We
have in Vermont two varieties of
clay, that of the low lands, which has
been carried from the mountains, and the
clay of the mountains, which has been
formed on the spot where it is found.
These two kinds are very different. The
hill clay is tougher and retains water
longer. 1t is not an agricultural clay. The
muck soil Is soil whose character is prin-
CIpally developed by the vegetable mat
Ter in It, II is formed by the partial decay
Of vegetable matter mixed with mineral
matter brought by overlooking water. If
water from the outside never came over
it, you would get i'll the end peat SOIL
made up almost altogether of vegetable
matter. The vegetable soil, mixed with
mineral matter is the richest of all. The
mechanical condition of the soil has IA
good deal to do with its fertility. The
grayeliy soils are the warmer the clay
the heavier and colder the sandy the
easier to till But the fertility of the soil
depends principally on its mineral com
position SO too the character of the soil
depends as much on the way the soil
came from the rock as the character of
the rock itself.
There are three great classes of rocks
from which the soils may be made The
sandstones, the llmestoneS and the gran
ties. The sandstones were originally de-
posted at the bottom Of the water. The
gritty part of the sandstone is Silica and
these grains are joined either by lime or
iron The limestOneS are made from some
kind of life, either vegetable or animal.
These stones have all been made at the
bottom of the water. The GRANTEES are
made by the action of heat. They are
composed of crystals. These rocks are
mixed they have no regular layers. The
rock in this part of Vermont is quite
variable 1t belongs to several different
series OF rocks. The soil OF Vermont con
talns Il large amount of potash. Gneiss
mixed with tale produces talchose schist
which occupies in extent nearly one-hali
the area of Vermont The general char
aCtsr OF he Darlington rock IL potash and
silica Three and one fourth per cent l.,
from the Green mountains to the lake.
This is about 900 pounds of potash
10 the acre, or enough for 1909 good crops.
Most of Vermont soil, on this side OF the
mountains, does not need potash. The
soil on the other side of the mountains
does. The native rocks q Vermont are
notably lacking in phosphoric acid; !e
the average of Vermont soil in this re
speCt is about as good as Western soil.
Plants need the following minerals fOI
their growth: PhosphateH, sulphates
chlorides, sillcates, magnesium, lime
soda and potash The inorganic part
forms the great part of the bulk of the
soil The action of the great bulk of the
soil is principally mechanical. The best
mechanical condition of the soil Is about
equal parts Of sand and clay. The clay
serves as the reservoir of plant food and
the sand as the YentilatOr.
The nitrogen OF the soil must originally
have come from the air, but 1t has now
become incorporated with the Foil.